New Zealand’s Geological Timeline
200 mya
 Proto NZ land area became home to many of endemic
species ancestors.
 Area close to Sth pole it was thought that it was too cold for
reptiles to colonise.
170 mya
 Gondwana slowly rotated allowing NZ to become warmer
 Major tectonic uplift, bringing NZ in contact with several
other (now separate) land masses. Low sea-levels allowed
reptiles and amphibians to cross over.
 Ancestors of modern native podocarps, native frogs, land
snails, earthworms, Tuatara and Weta are present.
144-110 mya
 Gondwana began to break up. Tectonic plates shifting and
spreading zones increase the distance between new separate
land masses. Species on these islands initially showed
similar genes but over time become more diverse until
viable interbreeding was no longer possible.
100 mya
 Beech trees entered NZ from South America where their
close relatives survive today. Colonisers had to be blown or
able to fly as the land had separated too much.
 NZ close to Sth pole therefore favoured dense beech
forests.
83 mya
 Separation process completed. Allows many forms to
survive for millions of years without competition and
predation from mammals.
 Birds now occupy the niches that were filled by mammals
and dinosaurs in other parts of the world.
60-65 mya
 Geological isolation in NZ meant that when the great
extinction event (Asteroid crashing into the earth sent dust
into the atmosphere blocking light – lowering temp) NZ
was not effected as much. NZ species were not affected to
the same degree.
 Mammals filled niches vacated by dinosaurs but absences
of mammals in NZ only added to it uniqueness.
 Further land movements allowed the short-tailed bat,
pohutukawa and others birds to immigrate.
54-33 mya (Eocene period)
 Antarctica moved to the poles – covered in ice
 End of vast beech forests
 Penguins arrived in NZ – NZ giant penguin 1.62m
33-23 mya (Oligocene period)
 Continual erosion – NZ was a few remnants in a shallow
sea.
 Competition for land and loss of habitat caused many land
species to be lost.
 Podocarp species became extinct.
 Kauri trees replace ancestors and clothed much of Nth
islands
 Plate boundary between Australian and Pacific tectonic
plates begin piling up sediments.
 Volcanic activity added to growing landmass – now more
space and ecological niches to fill.
23-5.3 mya (Miocene period)
 Takahe and Kakapo ancestors arrived about this time
 Many of native birds become large due to lack of predators
and many lose ability to fly. Gigantism in native birds.
10 mya
 NZ still a single land mass.
2.2 mya-presents
 Separation of Nth from Sth Island. (2mya)
 Sth Island was thought to be frozen in a period of glaciation
 12 Ice ages
 Changing sea-level rise greatly enhanced rate of
evolutionary change. During ice ages – Sea-level dropped
joining offshore islands to mainland by land bridges. This
allowed plants and animals to spread but then would
become isolated again as the sea-level rose during
interglacial periods.
 During isolation, populations on different island developed
different habits and food preferences. Adaptive radiation
was occurring. These would be retained when the next
come together during further ice ages. New species and
subspecies developed.
 Today NZ is a warm landmass in an interglacial period.